function  Trajectories ( a , b, u0, v0 )

GeneRegulation_Nullcline ( a , b );

t=linspace(0,10000,30000)';
uv0=[u0;v0;a;b];
[t,UV] = ode45(@Regulation_Function,t,uv0);
hold on;
plot(UV(:,1),UV(:,2),'b');

end

